In “Serving Herself: The Life and Times of Althea Gibson,” Ashley Brown, an assistant professor at the University of Wisconsin at Madison, describes the scene on the grounds, which should be among the most well-known trailblazing moments in American sports:

“One of the world’s leading symbols of white supremacy and White womanhood had presented a sterling silver salver to a Black woman, a descendant of slaves, while a stadium filled with colonizers cheered. These were role reversals for the ages.”

The public display Brown captures is incredible, but Gibson upended the gilded game more than once that unseasonably hot afternoon. A smaller moment in another new biography, “Althea: The Life of Tennis Champion Althea Gibson,” by Sally H. Jacobs, encapsulates just how fearless and confident Gibson was, both on and off the court. Jacobs, a Boston Globe reporter for many years, tells of Gibson letting Fraser know exactly where he stood in the tennis pecking order. In the Cold War era, when the modern civil rights era was just beginning to bubble up, a Black woman kicked racist and sexist norms to the curb and told a White man what’s what. It wasn’t the first time, nor would it be the last, that Gibson demanded she open the mixed-doubles service game, because “Big Al” goes first.

Does she ever. The number of Black — primarily, but not exclusively female — “firsts” that Gibson holds is staggering. There are the additional Grand Slam victories at the 1956 French Championships (now the French Open) and the ’57 and ’58 U.S. National Championships (now the U.S. Open), the covers of Sports Illustrated and Time, and the Associated Press athlete of the year awards. There are more subtle groundbreaking feats as well, like in 1951 in Miami, when she became the first Black player in a mixed-race tournament below the Mason-Dixon Line. For good measure, at age 36, she became the first African American member of the LPGA Tour. Her golf game never really got out of the bunker, but the historical record remains the same.

Before reading these biographies, I was aware of Gibson’s accomplishments, but it turns out that I knew next to nothing about this woman’s incredible life and career. I’m not alone. Given all she did for sports and society, it’s shocking that Gibson’s legacy is so muted today. Fortunately, Brown and Jacobs are here to reintroduce a supreme athlete every bit as important as Arthur Ashe or Billie Jean King. These books take different routes — disproving the notion that there’s such a thing as a “definitive” biography — but they end up at the same match point, making an airtight case that Gibson is the most undersung athlete in U.S. history.

Both Brown and Jacobs cover the entirety of Gibson’s life, from her troubled upbringing in a violent Harlem home to her time learning the game — and respectability politics — under the tutelage of two well-off Southern Black physicians; they move on to the peaks and valleys of a career that took her all over the globe on behalf of the United States while earning her next to nothing, and the tragic subsistence years toward the end of her life — a footnote, even as the Williams sisters took over the game. (Serena and Venus were steeped in tennis history, and both authors tell of touching correspondence between Gibson and her brilliant successors.)

Gibson’s journey provides so much material that it’s confounding that there hasn’t been a major biopic to this point. Who else toured with the Globetrotters, played an enslaved person in a John Wayne movie, sang on “The Ed Sullivan Show” and was briefly in charge of regulating boxing in New Jersey? I wouldn’t necessarily recommend reading these books back-to-back, but other than descriptions of low-stakes tennis matches against unknown opponents, the anecdotes Brown and Jacobs share are never boring. On the contrary, as when a thunderstorm erupted and lightning sent a stone-carved eagle crashing down from atop the stadium during Gibson’s first appearance at the U.S. Nationals, they can be biblical.

Where the books diverge are in style and tone. Both authors rely on reams of source material, but Brown, befitting an academic, goes deeper into the archives, particularly the African American newspapers of the day, while conducting only a few interviews. Jacobs, a journalist by trade, has the firsthand accounts of more than 100 people, including multiple (mainly White) octogenarian peers of Gibson. Brown’s book features denser historical digressions, whereas Jacobs’s is a bit lighter, but both women expound upon the political lay of the land and the complicated relationship Gibson had with the Black community.

Gibson’s brash, funny, exuberant personality leaps off the page, but so does the combination of naivety and obstinacy in her reiteration that she was “just another tennis player, not a Negro tennis player.” It’s a tension that permeates both books, adding some possible context for why Gibson has never gotten her due. She starred in the conformist 1950s, in an all-White sport. The wave of public athlete-activists was yet to come. Gibson was fiercely independent, but she came up in the nonconfrontational shadow of Jackie Robinson (an oft-made, clichéd comparison that she loathed). And Robinson at least had the support of Dodgers teammates, including Black players, from his second season on. Gibson was a loner in the loneliest sport, but she never let it get in the way of her hypercompetitive drive.

Gibson also dealt with a constant sexist drumbeat, often from the typewriter keys of the male sportswriters in the Black press. From Day 1, she was critiqued for her “manly” dress and style of play — a fast, powerful, serve-and-volley game highlighted by a wicked overhead smash — while continually having her sexuality questioned (and left unanswered).

Gibson grew up hard, attacking tennis like legendary boxer Sugar Ray Robinson, her early friend, mentor and Harlem neighbor. Her pugilistic me-against-the-world vision seemingly led her to believe, or at least to convince herself, that being Althea Gibson, politically chaste tennis champion, could overcome a racist, sexist society, giving her the life of fame and comfort she deserved. It didn’t. She dominated in the pre-Open amateur era, barely scraping by, and she had no substantial post-tennis career to speak of. Gibson’s dreams of being an entertainer were dashed when her 1958 jazz album flopped. She later served as New Jersey’s commissioner of athletics, but it wasn’t a lucrative gig. After a mid-’80s layoff, she became a heavy-drinking recluse in a Newark apartment, a world apart from the manicured Wimbledon grass. In the 1990s, tennis-world stars such as Billie Jean King and journalist Bud Collins raised money for the destitute Gibson, but there wasn’t much oversight. It’s unclear exactly where the money went. Gibson died in 2003 after a long and solitary period of ill health, an abandoned pioneer whose years of downtrodden hand-to-mouth exile are an American disgrace.

Althea Gibson never considered herself a crusader. Here’s hoping that these engrossing biographies help elevate her public stature to where it should be. One honor would go a long way to ensuring that her name is never forgotten. The idea was floated years ago and dropped, but the time has come to rename the third U.S. Open stadium, the Grandstand, after her. Media members and fans alike simply use shorthand for the other two stadiums, Ashe and (Louis) Armstrong. Knowing the third as Gibson would be a permanent reminder that Big Al went first.

Patrick Sauer has been a freelance writer for more than 20 years for many publications, some that still exist. He also co-hosts the live online talk show “Squawkin’ Sports,” which features interviews with authors of sports books.

The Life and Times of Althea Gibson

The Life of Tennis Champion Althea Gibson

St. Martin’s. 447 pp. $32